Answer:
pH = 2.4
Step-by-step explanation:
pH is defined as the negative log of the hydronium concentration.
Thus, we can plug in the given hydronium concentration:
pH = -log[H⁺] = -log[0.0042] = 2.4 (two significant figures)
The pH of the solution is 2.4.
P.S: Although I referred to [H⁺] as hydronium concentration, it is more accurate to express it as [H₃O⁺], though they are interchangeable and means the same thing.